Question: What is the mean of the 10,000 integers from 1 to 10,000, inclusive? Express your answer as a decimal to the nearest tenth.
Answer: The average of $1$ and $10{,}000$ is $5000.5$. We can replace both of numbers with $5000.5$ without changing the average of all the numbers. Furthermore, $5000.5$ is the average of $2$ and $9{,}999$, $3$ and $9{,}998$, and so on down to the pair $5{,}000$ and $5{,}001$. We can replace all of the numbers with $5000.5$ without changing the overall average, which must be $\boxed{5000.5}$.